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You can, but for small walls (which is my area of practice) it's cheaper to just throw concrete into a footing. It's actually very simple mechanics. If you get above 12-15 feet, the base of the wall starts to have exceptionally high stress and if there's good soil or sound rock available it makes sense to do a pinned design.

As soon as you start talking about rock anchors or soil nails, you've got a geotechincal firm involved and testing or borings to determine what your limits are. A small wall might run $2k in structural design and can be placed without knowing exact subsurface properties. The day you hire a geotech rig it's $6k to shake hands, and if you need detailed soil modeling you run into the tens of thousands before the structural engineer even picks up a pencil. For big, long walls, it's worth it. For a 12 foot tall wall that's only 60-100 feet long, it just doesn't make financial sense.

You ever see those huge sloped block walls in commercial construction (similar, but bigger than this)? They look like the same pavers they sell at Home Depot. That's gotta be a facade, right? I can't imagine those systems will really hold back 35' of earth.

I'm a total amateur on the subject, but I'm fairly sure you're talking about mechanically stabilized earth, where the wall face plays only a minor structural role. Frequently faced with hexagonal tiles for freeway on-ramps, but can be faced with basically anything. And here's a company website featuring the exact kind of wall you describe.

Mechanically stabilized earth (MSE or reinforced soil) is soil constructed with artificial reinforcing. It can be used for retaining walls, bridge abutments, seawalls, and dikes. Although the basic principles of MSE have been used throughout history, MSE was developed in its current form in the 1960s. The reinforcing elements used can vary but include steel and geosynthetics.

What you are talking about is a Segmental Retaining Wall. They are literally giant legos and extremely structural. The most common way to install them is you level them on a base of clean crushed stone, then stack and backfill with clean crushed stone. There is also a material called geo-grid and that gets laid back into the soil (distance is usually dictated by an engineer). So the grid gets tied into the wall, meaning if the wall tries to lean or push out, it now has to pull all the soil that’s on top of the geo-grid with it as well.

There are many walls 50+ feet and taller made from this system.

Source: I’m a certified SRW wall installer, the company I work for does a ton of them every summer. Most are usually small landscape walls around 4ft tall but once in a while we do some big ones.

Landscape architect here: Those are real blocks - they're stepped back from eachother, tied in to each other with various systems (some brands even use a little piece of plastic to hold block to block), then after 1.2 metres height you have geogrid tieing back into the hill, and every 3rd course or so depending on block size the geogrid gets repeated. OR you can use a gravity system wall where the bottom blocks are massive (they go deep back into the hill) and as you go up consecutive courses they get smaller - but this looks too high for that kind of system possibly. It's called a segmental retaining wall and is used to save money over a cast in place concrete wall.

I'm currently working on the design phase of a project where we'll use blocks almost identical to these to hold up an 8m shear wall (25ish feet). The secret is each of those blocks is attached to a high strength plastic/steel mesh that will run back into the embankment and hold the wall up.
Magic.

Judging from the picture, those blocks are a good 80lbs. If they are versa-lok, the standard is 83 lbs. When building with materials like this, you sink (or toe in) 10% of your total wall height. This keeps the bottom from pushing out.
As you build up, you step each block back an inch or so depending on the block. This puts the weight towards the hillside, and reduces back pressure. As you build up, you backfill with clean gravel at an angle like an upside down triangle. This allows water to fall to the bottom of the wall where you have drainage installed.
When building a wall over 4' tall, it's common practice to install geogrid (a high strength mesh fabric) that runs as far back (level) into the hillside, as tall as the wall. If your wall is 4' you have 4' running back into hillside. You install that every 2' after 4' of height.
If done properly, these types of walls will last for a long time without failure.
Source: building walls/ hardscaping has been my job for 10 years

Here's a quick one for you. I'm studying civil right now and I have more than a passing interest in geo. My dream job would be working for a geotech firm mitigating natural disaster damage. How does one get into those sweet geotech jobs? Graduate degree required?

A MS is preferred but nowhere near necessary. My advice is to get your BS, take the FE exam, find a job - ideally in a smaller firm. Smaller firms tend to need people to do more things, and you're less likely to get stuck doing the same thing day after day.

Ideally, you're job would be close enough to a university that you can go back to school after a couple of years to get a MS in the evening. What you learn, after being out and working for 2-4 years, will be far more valuable than if you plow straight through. Also, if you end up in a larger firm they may pay for your school (or give you a partial reimbursement).

As for the mitigating disaster damage, keep an eye out for firms which deal in high-damage areas. It's sort of up to what you like. Liquifaction damage on the west coast in high-eq zones; poor soils in WA and BC (think Seattle/Vancouver). Maybe a firm that has done stabilization of SOCal coastal areas? East coast you're looking at Hurricanes, so that's sandy soil and pile work on the coast from the FL keys up through SC. Maybe around the Gulf, but those tend to have poorer areas (on the whole) and less enforcement around preparing for hurricanes.

I'm structural, and started life as an aerospace, so I never did the soil thing most CEs do. I live in a college town so I've gone back and audited several soil classes (along with several graduate structures classes) to learn a bit more of the background. It's interesting stuff but my days are full enough with the above-ground portion of projects.

I just did this on a project. Soil nails, wire mesh and gunnite. 15’ h x 200’ long cost me $98,000 and that was just to stabilize the soil so we could get out concrete contractor in the area to build the wall.

I wish you were around CT so I could have you look at this retarded wall that’s cracked. But not so easy to pull the dirt back from, tear down, and replace with drainage. As the cement in the wall (it’s all poured) is ... connected to that part of the house foundation. Like they just made a 12’ long by four feet high perpendicular section just to hold back dirt in the 1940’s. That’s now cracked and leaning.

Blah. I’m probably just gonna sister a wall in front of it and drain it and then just sell the house like you would with a car with a knocking engine.

Well, fwiw, when a retaining wall starts to go, the answer is "replace it" 90% of the time. There are some fancy things we can do on historic sites, or if there are extenuating circumstances (supporting a building) - but it's usually cheaper to replace than fix. Fancy engineering is expensive, and installing fancy engineering is super expensive. Wish it weren't so, but sometimes it just is.

If there's proof that you willfully covered up something to pass on to a future homeowner - aka covering up a bodged retaining wall to sell the house - the future homeowner can sue the pants off of you and your contractor.

In other words, remember to delete this post before you list the house.

From a background in civil construction/earthworks, I’ve built both earth and rock retaining walls.

For larger walls you can use use rock-bolting, or mechanically stabalised earth, or just have big footings.
To build a mechanically stabilised retaining wall you first dig out all the earth behind it. Then place the wall in layers. As well as the mesh in layers, and the earth in layers too. I’ve built a large wall before, it was tied back 8m into the soil, and had one layer of mesh for every metre in height, up to 10 metres tall.
The soil has to be compacted in 200mm thickness layers in order to make it all dense enough.
The front back of the wall has rock filled mesh baskets.
You can imagine that 10m high and 8m tie in makes for a lot of dirt (this thing was about 50m long!)

Rock bolting obviously requires rock, so is less common for those nice looking walls holding back a bunch of earth. But it achieves the same result. Rock bolts were drilled into the rock face every 2 or so metres (in my case) and they were attached to all the reinforcement. And then a shotcrete (spray concrete) layer was sprayed onto the wall to support the rock face.

And then with footing designs there’s a whole bunch of options, sometimes because of ground conditions you don’t have the option for a footing to go deep. So what you can do is design a footing in a L shape so that the weight of the earth being supported as acts to prevent the footing from tipping, because it sits on the toe of the L.

Earthworks is fascinating but you never get to see anything because it all get buried!

Earthworks is fascinating but you never get to see anything because it all get buried!

When I get dragged to proposal meetings by Architects, my presentation usually includes the phrase "If I do my job right, you'll never even know I was on the design team after the structure is completed."

Unless it was heavier than tge hill (it’s not) it would only be cosmetic. You’ve got to have something to anchor the wall into the soil. Picture long attachments at each layer of the wall that reach back into the hill and you keep running them into the hill behind the wall as you build up the wall. That way if The Hill pushed forward like this one the wall would be held firm to the front of it. More importantly, the wall would help the soil behind it maintain its shape and integrity rather than just running all over.

Thank you. I've been wanting to do a DIY project that involves widening our driveway, but will require a maybe 2-3ft retaining wall. I've been trying to find good videos/resources about how to build a secure one that's not just stacked interlocking stones with a shallow footing. Not too many resources out there. Not going to try it until I feel confident what I did won't topple over and dent the car.

If your retaining wall is only 2 or 3 foot high you won't have to worry about all that much. Biggest thing you will actually have to deal with is up heaving do to frost and if you can put in a couple deadmans it shouldn't ever move.

Sure hope no one was taking there break in their car when this happened

Edit: thanks for the reddit gold kind stranger, i did notice i used the wrong "they're" but was too lazy to change my post it was set in stone, thank you for correction and i loved reading all the comments that followed never a dull moment.

Not just that, but your family and friends have to process it. It's one thing to die of illness or even a common accident like a car crash. But to have an unexpected act of god drop 10,000 lbs of concrete on your ass, while you are putting down a footlong sub on your lunch break, has to be incredibly difficult to process. It just hits them with complete shock.

I remember this one GIF of some security footage. A guy was walking near a tall rolling gate in some parking lot and the gate fell towards him, and it sandwiched his neck on the only object around which was the edge of an open plastic trash can in the middle of the road. He died instantly from a broken neck. Imagine having to grieve that. The trash can wasn't even supposed to be there.

Truly a freak accident. Every researcher and public health professional will treat it as an outlier. Everything happens for a reason, and I don't mean that disasters are justified, nor do I mean there was some kind of divine reason for their deaths, but no one is going to spend the resources to seek out a better explanation to give their families and friends than bad luck.

Ancient Han texts actually show that the Wanli changcheng (Great Wall) was actually only publicly announced as a defense against Mongols as a cover story - the actual reason for its construction was to serve as a 20th and 21st century tourist attraction.

You must not have very good insurance representation. My insurance agent bird dogged the fuck out of my apartment complex’s insurance when something similar happened to me. Said they weren’t going to pay. Spoiler....they paid.

Vehicles are almost never covered in property insurance policies. A tree falling on a car is a classic example of a claim that will be covered by the comprehensive insurance of the vehicle owner, assuming they have any. If they don't, the owner is SOL unless they can prove negligence against the tree owner.

The car owners in this situation probably have a valid claim that the retaining wall was deficient, so they might have a claim against the organization.

This happened in the morning of Sep 8, 2017, at a weather station in Yunnan province, China.
The wall collapsed down because of consecutive rainy days.
10 cars were flattened but no one was killed or injured.

Years ago myself and many others watched a 15 foot retaining wall made of stacking blocks collapse onto the entire row of about 30 cars. It was the most awesome whoosh and bang I've ever heard. Really glad I parked in the front lot that day.